cherry7girl
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part of the question: In women, the first division of meiosis produces one daughter cell that has almost all of the cytoplasm. The other daughter cell consists of a nucleus surrounded by a very small amount of cytoplasm and a cell-surface membrane. This very small daughter cell is called a polar body. Polar bodies do not usually divide. The same process occurs in the second division of meiosis, resulting in one egg cell and two polar bodies.

Mitochondrial diseases are caused by faulty mitochondria. All of a person’s mitochondria are inherited from their mother via the egg cell. An egg cell contains approximately 3 × 105 mitochondria.
One proposed treatment to prevent passing on faulty mitochondria involves
• removing the nucleus from an egg cell donated by a woman with healthy mitochondria
• replacing this nucleus with the contents of the polar body from a woman whose egg cells are affected by mitochondrial disease.
Suggest how this treatment prevents inheritance of mitochondrial diseases.

the answer: 1. Egg (created) has nucleus / DNA / genes of (affected) woman / mother;
2. It has mostly / many / lots of normal mitochondria (of unaffected woman)
OR
There are few faulty mitochondria;

i dont get this at all
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tbi_zlx
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Report 10 months ago
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(Original post by onedance1)
part of the question: In women, the first division of meiosis produces one daughter cell that has almost all of the cytoplasm. The other daughter cell consists of a nucleus surrounded by a very small amount of cytoplasm and a cell-surface membrane. This very small daughter cell is called a polar body. Polar bodies do not usually divide. The same process occurs in the second division of meiosis, resulting in one egg cell and two polar bodies.

Mitochondrial diseases are caused by faulty mitochondria. All of a person’s mitochondria are inherited from their mother via the egg cell. An egg cell contains approximately 3 × 105 mitochondria.
One proposed treatment to prevent passing on faulty mitochondria involves
• removing the nucleus from an egg cell donated by a woman with healthy mitochondria
• replacing this nucleus with the contents of the polar body from a woman whose egg cells are affected by mitochondrial disease.
Suggest how this treatment prevents inheritance of mitochondrial diseases.

the answer: 1. Egg (created) has nucleus / DNA / genes of (affected) woman / mother;
2. It has mostly / many / lots of normal mitochondria (of unaffected woman)
OR
There are few faulty mitochondria;

i dont get this at all
As polar bodies do not divide they will not be able to carry the gene for faulty mitochondria so more normal mitochondria found due to there being the allele for unaffected mitochondria being passed on
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cherry7girl
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Report Thread starter 10 months ago
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(Original post by tbi_zlx)
As polar bodies do not divide they will not be able to carry the gene for faulty mitochondria so more normal mitochondria found due to there being the allele for unaffected mitochondria being passed on
One proposed treatment to prevent passing on faulty mitochondria involves
• removing the nucleus from an egg cell donated by a woman with healthy mitochondria
• replacing this nucleus with the contents of the polar body from a woman whose egg cells are affected by mitochondrial disease.


im so confused as i dont understand this part, to me it's saying they put the polar body into the healthy egg ? i dont understand what this does and how come there's an allele for unaffected mitochondria? sorry idk why im struggling so much to understand this, i hate reproduction so much
Last edited by cherry7girl; 10 months ago
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OxFossil
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Report 10 months ago
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(Original post by onedance1)
One proposed treatment to prevent passing on faulty mitochondria involves
• removing the nucleus from an egg cell donated by a woman with healthy mitochondria
• replacing this nucleus with the contents of the polar body from a woman whose egg cells are affected by mitochondrial disease.


im so confused as i dont understand this part, to me it's saying they put the polar body into the healthy egg ? i dont understand what this does and how come there's an allele for unaffected mitochondria? sorry idk why im struggling so much to understand this, i hate reproduction so much
Mitochondria have their own genome, separate from the nuclear genome. But obviously, most of a persons DNA is contained in the nucleus. So the selected cell will now contain the polar body from the recipient mother - which (as far as we know), contains normal nuclear DNA, and a few faulty mitochondria - but because it is now housed in the healthy donor cell body, most of the new cell's mitochondria will be healthy ones, from the healthy donor cell.
Last edited by OxFossil; 10 months ago
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